INFO: scanf() with %i and a Leading 0 Gives Octal Conversion

 Last reviewed: September 2, 1997
Article ID: Q49573

The information in this article applies to:
  • The C Run-time (CRT) included with: - Microsoft C for MS-DOS, versions 5.1, 6.0, 6.0a, 6.0ax - Microsoft C for OS/2, versions 5.1, 6.0, 6.0a - Microsoft C/C++ for MS-DOS, version 7.0 - Microsoft Visual C++ for Windows, versions 1.0, 1.5 - Microsoft Visual C++ 32-bit Edition, versions 1.0, 2.0, 4.0, 5.0

SUMMARY

In Microsoft C, scanf() may return different results when using the %i switch than when using the %d switch. With the %i switch, reading in a number that begins with a 0 (zero) will cause the number to be treated as an octal number. The %d switch treats all numbers as decimal numbers.

MORE INFORMATION

The %i switch has the capability of reading in decimal, octal, and hexadecimal numbers. Hexadecimal numbers are specified with the 0x in front of the number, while octal numbers are specified with the 0 in front of them. If you want only decimal numbers to be read in, use the %d switch.

This is expected behavior and occurs with the entire scanf() family.

Additional query words: sscanf fscanf
Keywords : CRTIss kbfasttip
Version : MS-DOS:5.1,6.0,6.00a,6.00ax,7.0; OS/2:5.1,6.0,6.00a; WINDOWS:1.0,1.5; WINDOWS NT:1.0,2.0,4.0,5.0
Platform : MS-DOS NT OS/2 WINDOWS
Issue type : kbinfo

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Last reviewed: September 2, 1997
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